Cylindrical bodies from polyethylene or polypropylene

ABSTRACT

Cylindrical bodies from polyethylene or polypropylene fabrics are prepared with tensile strength at least 22 kg/50 mm, in the bonded and unbonded portions.

United States Patent 1 1 I Takeda [54] CYLINDRICAL BODIES FROM POLYETHYLENE R POLYPROPYLENE [76] inventor: Shigekazu Takeda, .No. 141, 1--

chome, Chofumine-machi, Ohta-ku, Tokyo, Japan 22 Filed: Jan. 11, 1971 21 Appl.No.: 105,316-

R elated US. Application Data [62] Division of Ser. No. 649,556, J1me 28, 1967, Pat. No. I

[] Foreign Application Priority Data July 4, 1966 Japan ......41/43431 Sept. 8, 1966 Japan ..4l/59594 [52] US. Cl. ..l61/92, 156/270, 156/306,

[51] Int. ..'...'...B32b 3/26, B321: 7/14 1March 20, 1973 [58] Field of Search 1.61/88, 92, 139,178, 252, 161/86, 127,147, 149, 402, 138/123; 139/387-390; 156/203, 204, 218,

Primary Examiner-William A. Powell v Attonrey- Bu'eknam and Archer [57] ABSTRACT Cylindrical bodies from polyethylene or polypropylene fabrics are prepared with tensile strength at least 22 kg/SO mm, in the bonded and unbonded portions.

5 C1aims, 2 Drawing Figures CYLINDRICAL BODIES FROM POLYETHYLENE OR POLYPROPYLENE This application is a Division of Ser. No. 649,556, filed June 28,1967, now US. Pat. No. 3,597,292.

This application relates to novelcylindrical bodies from synthetic resins. I

There has heretofore been no chemical binder materials such as fabrics (cloths) or films made of synthetic resins, e.g., polyethylene, polypropylene or the like; and there has therefore been conventionally welded, at its opposing brim portions, into a cylinder on the bonding apparatus; and I .'available for satisfactorily effecting a bond between .used a method by which thermoplastic resin fiber fabrics are, per se, thermally welded or heat sealed without the use of any chemical binder or welding agent, to prepare bags or the like from the fabrics- The bags so obtained have been satisfactory for use as containers for light duty purposes, for example, for holding light goods therein. On the. other hand, if thermoplastic resin bags having a voluminal size enough to hold 50 kg. of chemical fertilizer such as particulate ammonium sulphateare prepared using said conventional method, loaded with 50 kg.- 'of the fertilizer through its opening and entirely closed by heat'sealing the opening also using the method, and then subjected to a free drop test (the bags are allowed to drop at an altitude of 1.5 m. above the concrete floor), they will be broken at the heat-sealed portions and/or their adjacent portions. This is because the sealed portions and/or their neighborhoods subjected to the heat dur-' ing the heat-sealing operation .are made thinner than the remaining portions not subjected to that heat; And therefore, the former portions become of less strength than the latter. Thus, the bags prepared from thermoplastic resin cloth using the conventionalhe'at-sealing method are generally unsuitable for and, in many cases,'cannot be used for the heavy duty purpose as mentioned above.

It has now been found that even thermoplastic resin bags for heavy duty purposes can easily be manufactured from thermoplastic resin cloth using as a binder the same resin as the cloth.

This invention relates to a novel process for effecting a bond between polyalkylene fiber fabrics, the bond being substantially unbreakable without damaging the fabrics. More particularly it relates to a process for effecting such an unbreakable bond between fiber fabrics of thermoplastic resin such as polyethylene, polypropylene or the like by applying, as a binder, the same resin in a molten state -as the fabrics to the selected portions thereof to be bonded, slightly pressing against each other the portions with the still molten resin therebetween to effect a preliminary bond, and then additionally pressing and simultaneously cooling the preliminarily bonded portions to complete the bonding.

It is an object of this invention to provide thermoplastic resin bodies exhibiting high tensile strength both in the bonded and non-bonded portions.

It is still another object of this invention to provide tubular or cylindrical thermoplastic resin fiber fabrics which are, per se, useful for some specific purposes and from which excellent bags for heavy duty uses can easily be manufactured by further using the process of this invention in combination with those described in the copending Japanese Applications (Pat. applications FIG. 2 is a diagrammatic cross-sectional view of th cylinder only to show the structure of the welded portions thereof. I

According to one aspect of this invention, a polyethylene, polypropylene or the like fiber fabric is welded so that it may be formed into a cylinder by folding one of the opposing brim portions of the fabric just over the other while placing, as a binder, the. same resin in a molten state as the-fabric in a gap between the almost overlapped brim portions to be welded, slightly pressing against each other the overlapped portions with the still softened binder therebetween to effect a preliminary bond between the portions, and then additionally pressing the preliminarily bonded portions tions including the binder therebet ween whereby the bond is completed.

More particularly the thermoplastic resin fiber fabric can be made into a cylindrical form on the bonding apparatus of this invention by folding one of the opposite brim portions of the fabric just over the other so that they are somewhat overlapped each other while applying a resin of the same kind as the fabric and molten at a temperature of about 240 290 C, preferably 250 275 C, to the brim portion sides which are' opposite to each other and to be bonded by means of an applicator attached to the bonding apparatus in such a manner that the molten resin applied may form its band-like layer between the portions as the fabric moves on the apparatus longitudinally along the axis thereof, slightly pressing the portions against each other to preliminarily melt join the lower'side of the layer with the upper side of the lower brim portion simultaneously with melt joining the upper side of the layer with the lower side of the upper brim portions, and then passing the thus-obtained cylindrical fabric with the preliminarily joined portions through between a cooling device to thereby apply additional pressure to and simultaneously cool the preliminarily joined portions for the completion of the joining. When the fabric used in the process of this invention is an' endless one, the fabric cylinder obtained will of course be an endless one which may be cut into suitable long cylinders for use in the preparation of bags therefrom further using the joining technique according to this invention.

Referring now to FIG. 1, numeral indicates an endless thermoplastic resin fiber fabricv such as a polyethylene fiber cloth. The fabric 1 is passed over a guide roll 9 through under a nozzle 6 towards a rotary cutter 12. The brim portions 2 and 3 of the fabric 1 are initially turned up and then gradually folded one upon another (the brim portion 3 is folded on the brim portion 2 in this case) by means of a width adjusting plate 4 and folding guide plates 5. As a binder, molten resin which is materially the same as the fabric is applied at about 240 290 C to the opposite sides of the almost overlapped brim portions 2 and 3 through the nozzle 6 titude of 1.5 m. above the concrete floor); the results of I the tests showed that any of the bags loaded with the granular material was not broken and still remained unchanged in appearance after the test.

In order to make sure the most remarkable advantage in that an improvement is made in tensile cooling rolls 11 to press additionally and cool the preliminarily bonded portions for the completion of the bonding. A coolant used for. the cooling rolls can be water, and if desired in hotclimates, brine cooled 'by a refrigerator niay be used for the same purpose. The

endless fabric cylinder is moved forward on the bonding apparatus and then cut by the rotary cutter 12 into suitably long cylinders which are mainly intended to be used in the preparation of bags for heavy duty purposes. The pressing rolls and cooling rolls 11 may additionally be used as feeding rolls by which the fabric is fed. i

In FIG. 1, there is shown only one pair of cooling rolls, and, however, two ormore pairs of cooling rolls should be used if the feeding rate 'of the fabric is desired to be higher. On the bonding machine, the endless fabric cylinder formed can finally be cut into cylinders of any axial length desired with the rotary cutter 12 by I adjusting the rotation pitches thereof. The thus-cut cylinders can each be formed into a bag, particularly a heavy-duty bag by treating (cutting, bondingand the. like) one of the open ends of the cylinder in such man-. ners as' described in said copending Japanese patent and utility model applications.

g A fabric normally used in the process of this invention is one which is manufactured from polyethylene or polypropylene flat yarns (stretched tapes) by interweaving thern'untwilled (plain), or is one which is prepared. by laminating a polyethyleneor polypropylene film to the plain fabric as mentioned above.

' The inventors experiences have shown that a bag prepared from such a film coated fiber fabric as above byapplying the bonding technique of this invention to the fabric can be used as a satisfactory container for holding 'up to about 50 kilogramsof a powdery 'or granular substance such as chemical fertilizer even if the substance is hygroscopic, that a bag prepared from a fabric which is the same as the above except that it has no film coated thereon can be used as a satisfactory container for holding about the same amount (in weight) of such a powdery vor granular substance as mentioned above only whenv the substance is nonhygroscopic, and that a bag prepared from polyethylene or polypropylene'film (not fabric) in the same bonding manner as above can only be used as a container'for holding therein not more than about half the amount of either ofthe above substances.

For the purposeof tests for the toughness of bags, 50 kilograms ofa granular material (chemical fertilizer) were putin'each of the bags (some prepared from a fabric without film coating thereon and other from a film coated fabric by applying the bonding technique of this invention to the. fabric), and then the bag loaded tion and subjected to a droptest (dropped at an alstrength of the portions bonded according to this invention, the following tests were made using two groups of test'samples, one group consisting of .the samples prepared by binding together two pieces from polyethylene film coated polyethylene fiber fabric at their brim portions according to this invention and the other by sewing up two other pieces from the same bound-together according to this invention are increased in tensile strength by approximately 35 percent, compared with those sewn up by the. sewing machine according to the conventional'method.

Though the bonding process of this invention has so far been explained about its use ineffecting'a bond between polyalkylene fiber fabrics, it is to be understood that this process can also be applied to effecting a bondbetween the polyalkylene substances in any form, for example, between atape and a'fabric to reinforce the former in strength.

This invention will be betteriunderstood by the following Examples.

EXAMPLE 1 Polyethylene fiber fabrics or cloths (88 g/m used in this Example consisted of 1,000-denier polyethylene tapes or flat yarns (0.960 g/cc, 5.01 g/d, elongation 18.04 percent, melt index 3.0) interwoven untwilled resin binder in a molten state to the opposite sides of j the portions to be bonded, slightly pressing against each other the portions with the still molten binder therebetween and then cooling and additionally pressing them against each other to complete the bonding. The operational conditions employed in this Example were as follows:

feeding rate of fabric 50 m/min temperature of molten binder through nozzle 265C width of overlapped portions 40 mm width of binder layer formed between overlapped portions 15 mm amount of binder applied l.8 glm final pressure exerted on binder-applied portions 6.0

kg/cm cooling temperature C The polyethylene composing the fabric was the product (trade name: Shorex, Grade No. 6,000'F) made by the Showa' Denko K. K. and-that used as a binder the product (trade namez'Yukalon LK-30) by the Mitsubishi Petrochemical Co., Ltd.

portions and tapes together by the use of a sewing machine (SD4 type made by the New Long Co.) under the following conditions:

stitching pitch 8 mm 7 sewing treads vinylon (polyvinyl alcohol) /2 X 3 For comparison, the original fiber fabrics, the portions bonded of the fabric cylinder according to this invention and the portions sewn up of the fabric cylinder by the conventional method were sampled and tested which the warps or .wefts run, perpendicular to the line formed by the bonding,'and perpendicular to the line formed by the sewing, respectively, using an Instron type tensile strength tester under the following conditions:

rate at which sample stretched 1 cm/min effective length, of sample, to which tension applied 200 mm width of sample 50 mm temperature and humidity at which "test made 20C and The. results obtained from the tests are shown in Table 1. 1

TABLE 1 Tensile tenacity (Kg/50 mm) Original Sample fiber Portions Portions No. fabric bonded sewn up 1 48 22 7 2 48 24 7 3 44 28 8 4 46 28 7 5 44 26 8 mean value 46 26 7 EXAMPLE 2 The procedure of Example 1 was followed in this Example except that the fabric used had 105 g/m in weight, 12 yarns/inch in warp density and 12 yarns/inch in weft density, the feeding rate of fabric was 40 m/min,

No. fabric bonded sewn up 1 54 34 15 I 2 52 30 12 3 54 30 13 4 50 32 ll 5 52 30 13 mean value 52 32 13 EXAMPLE 3 The procedure of Example 1 was repeated except that the fabric had a weight of 140 g/m a warp density of 16 yarns/inch and a weft density of 16. yarns/inch, the feeding rate of the fabric was 40 m/min, the width of binder layer formed 13 mm and the amount of for their tensile tenacity in a direction parallel to that in binder applied 2.2 g/m.

The tensile tenacities are indicated in Table 3.

TABLE 3 Tensile tenacity (Kg/50 mm) Original Sample fiber Portions Portions No. fabric bonded sewn up l 70 52 l9 2 66 42 21 3 66 48 21 4 48 46 l8 5 64 48 20 mean value v 66 48 20 EXAMPLE 4 the width of binder layer formed was 17 mm and the TABLE 2 Tensile tenacity (Kg/50 mm) Original Sample fiber Portions Portions The procedure of Example 1 was followed except that the fabric was a 0.05 mm thick polyethylene filmlaminated polyethylene cloth, it had a weight of 124 g/m, a warp density of 9 yarns/inch and a weft density of 9 yarn/inch, the feeding rate was m/min, the temperatureof molten binder 255 C, the width of binder layer formed l6 mm and the amount of binder applied 1.7 g/m.

The film (Yukalon, Grade No. 800 made by theMitsubishi Petrochemical Co., Ltd.) was such that it was thermally laminated on one of the sides of the fabric.

The tensile tenacities. determined using said tensile strength tester are shown in Table 4.

TABLE 4 Tensile tenacity (Kg/50 mm) Original Sample fiber Portions Portions No. fabric bonded sewn up i 57.6 38.8 28.6 2 60.3 37.7 28.3 3 58.5 37.4 27.8 4 57.8 39.2 28.5 5 I 58.9 38.5 28.1 mean value 58.6 38.3 28.2

EXAMPLE 5 The tensile tenacities measured are listed in Table 5.

TABLES Tensile tenacity (Kg/50 mm) Original Portions Sample fiber Portions No. I fabric bonded sewn up i 1 64.7 43.5 29.7 2 65.2 40.7 3L3 3 63.8 4L2 32.8 4 63.6 40.8 30.1 5 a 64.4 41.3 29.3 mean value I 64.3 4L5 30.6

EXAMPLE 6 The procedure of I Example 1 was followed except that the fabric was such that it was thermally laminated with a 0.06 mm thick polyethylene film, it has a weight of 156 g/mQa warp density of 12 yarns/inch and a weft density of 12 yarns/inch, the temperature of molten binder applied was 270 C, tlie width ofbinder layer 19' mm and the amount of binder applied 2.4 =g/m.

The tensile tenacities'obtained are shown in Table 6.

TABLE- Tensile tenacity Kg/50 mm) Original Sample fiber Portions Portions No. fabrics bonded sewn up l 68.9 43.8 33.8 2 69.7 44.3 32.6 3 69.8 43.7 33.6 4 70.6 44.7 31.2 5 70.8 43.5 34.5 mean value 69.9 44.0 33.]

EXAMPLE 7 fonned on the fabric 18 mm and the amount of binder I EXAMPLE8 The same procedure as in Example '1 was taken in this Example except that the fabric used was a polypropylene fiber fabric 136 g/m), the temperature of molten binder used 260 C, the width of binder layer applied to the fabric 1.6 g/m.8

-.The fabric used was made of polypropylene (trade I name: Chisso Polypro) manufactured by the Chisso Sekiyu Kagaku K. K and the resin used as the binder The procedure. of Example 1 was followed except I that the fabric was a polypropylene fiber fabric having a weight of 84 g/m', the-feeding rate of fabric was 40 m/min, the-temperature of moltenbinder ejected 255 C., the width of binder layer formed on the fabric l3v mm andt'he amount of binder applied to the fabric 1.4

,. glm. In addition, the polypropylene used for the fabric was the product (trade name: Mitsubishi Noblen) made by theMitsubishi Yuka K.K., and that used as the binder was the product (trade name: Mitsubishi Noblen fFA-3) made by the'same' manufacturer as above.

, The tensile tenacities determined are enumerated in Table 7. I

TABLE7 Tensile tenacity (kg/ m'm) Original Sample fiber Portions Portions No. fabric bonded sewn up I 42 35 30 2 40 36 33 3 43 34 29 4 39 35 31 5 44 33 30 mean value 42 3l was polypropylene (trade. name: Mitsubishi Noblen FAA-3) made by the Mitsubishi Yuk a K.K.

The procedure of Example was followed in this Example except that the plain fabric was made of polypropylene (trade name: Chisso Polypro), it had a weight of I32 glm, awarp density ofl4 yarns/inch and a weft density of 14 yarns/inch, the feeding rate of the fabric was 40 m/sec, the temperature of molten binder 270 C, the width of binder layer formed on the fabric 18 mm and the amount of binder applied to the fabric 2.0 'g/m. The resin used as the binder was polypropylene (trade name: Mitsubishi Nobulen FA- 7 3) made by the Mitsubishi Yuka K. K. I

The tensile tenacities determined using said tester for A tensile strength are shown in Table 9;

TABLE 9 Tensile strength (Kg/50 mm) ean value Original Sample fiber Portions Portions No. I fabric bonded sewn up I 42 35 30 2 40 36 33 3 43 34 29 '4 39 35 3| 5 44 33 30 m 42 35 31 What is claimed is:

l. A polyethylene or polypropylene fabric cylinder consisting of stretched fibers of polyethylene or polypropylene wherein the weight of the fabric is between 84 and 156 gms/m having a tensile strength at the non-bonded portions between 46 and 58 kgs/SO mm and a tensile strength at the bonded portions at least 22 kg per 50 mm and wherein the bond has been formed by a binder which consists of the same subof -16 yarns per inch and a weft density of 10-16 yarns per inch and the tensile strengtl'i at the bonded portion is up to 52 Kg/SO mm.

4. The cylinder according to claim 1 wherein the fabric is a polyethylene film-laminatedv polyethylene cloth and the tensile'strength at the bonded portions is up to 44 Kg/SO mm.

5. The cylinder according to claim 1 wherein the fabric is a polypropylene fabric and the tensile strength is upto 36 Kg/SO mm. 

2. The cylinder according to claim 1 wherein the fabric is 1000-denier polyethylene tapes.
 3. The cylinder according to claim 1 wherein the fabric is flat yarns of polyethylene with a warp density of 10-16 yarns per inch and a weft density of 10-16 yarns per inch and the tensile strength at the bonded portion is up to 52 Kg/50 mm.
 4. The cylinder according to claim 1 wherein the fabric is a polyethylene film-laminated polyethylene cloth and the tensile strength at the bonded portions is up to 44 Kg/50 mm.
 5. The cylinder according to claim 1 wherein the fabric is a polypropylene fabric and the tensile strength is up to 36 Kg/50 mm. 